1. Field of the Invention
The invention relates to a fuel cell system which can be operated with liquefied petroleum gas.
2. Description of the Prior Art
Fuel cells require hydrogen and (atmospheric) oxygen as reactants for the generation of electrical and thermal energy. There are different known reforming methods, such as steam reforming, autothermal reforming, partial oxidation or cracking, wherein gas which contains hydrogen is generated by the conversion of gaseous and liquid hydrocarbons. In most cases, these methods are highly complex and require a high complexity in terms of apparatuses and technical control systems. Usually, they comprise a multitude of single components, such as reforming reactors, shift stages, gas fine-cleaning stages, heat exchangers, and vaporizers.
Furthermore, there are known high-temperature solid oxide fuel cells (SOFC) and molten carbonate fuel cells (MCFC) wherein gaseous and liquid hydrocarbons are turned into electrical energy at temperatures ranging from 600° C. to 1000° C. and under addition of (atmospheric) oxygen, this being achieved directly or with what is called a pre-reforming stage being connected ahead. The disadvantages of these systems are a low thermal cyclability, long heating and cooling times as well as very high requirements for the materials used.
Fuel cell systems have also, for some time, been used as APU systems (auxiliary power unit) for the supply of recreational vehicles with onboard power. It is also known to use such fuel cell systems as electric generators or cogeneration systems for decentralized energy supply.
US 2002/0182458 A1 describes a fuel cell system wherein it is also possible to supply propane as fuel in addition to other fuels. The fuel is processed in a reformer which is designed as an autothermal reactor and is converted into a hydrogen-containing reformate gas. The reformate gas is then supplied into an anode reaction chamber of the fuel cell via a heat exchanger.